A small migrant labor bus landed on its side after it ran off the road and hit a median, then landed on its side, according to St. Lucie County Sheriff Ken J. Mascara.
The incident took place around 6:30 p.m. on State Road 70 in rainy conditions, the Sheriff said.
Of the 13 on board, nine were transported to local hospitals with minor injuries. The labor bus was headed east when the accident took place.
The bus is owned by Triple H Inc., of 1800 Juanita Ave., Fort Pierce.
The investigation is under way at this time.